A Free Syrian army fighter stands on a damaged military tank Sunday in Zabadani, near Damascus, Syria. (AP)

Secretary of State John Kerry speaks during a news conference Monday with Britain's Foreign Minister William Hague at the Foreign and Commonwealth Office in London. Kerry said the solution to the Syrian conflict must be political not military but that air strikes were essential to stop the Assad regime from killing its own people with chemical weapons. (Susan Walsh / AFP via Getty Images)

WASHINGTON — President Obama is hitting the airwaves to try to convince Americans that limited strikes against Syria are needed for the United States’ long-term safety, while Secretary of State John Kerry is vehemently defending the case against President Bashar Assad, saying his denial of chemical weapons use is “contradicted by fact.”

Obama on Monday planned to make his case for punishing Assad for what the United States argues was his decision to use chemical weapons against his own people — a charge Assad denied in a new interview.

Assad warned of retaliation against the U.S. for any military strike in Syria. “You should expect everything,” Assad said in the interview aired Monday on CBS’ “This Morning.”

Asked if he was making a threat of a direct military response to an attack, Assad was vague, saying at one point, “I am not fortune teller to tell you what’s going to happen.” He added: “It’s not only the government (that’s) the only player in this region. You have different parties. You have different factions. You have different ideology. You have everything in this region now. So you have to expect that.”

Obama administration officials, meanwhile, planned more classified briefings on Capitol Hill. And White House national security adviser Susan Rice is scheduled to speak at a Washington think tank timed to the public relations blitz aimed at ensuring people the administration isn’t contemplating another commitment like Iraq and Afghanistan.

In the new interview, Assad told American journalist Charlie Rose there is no conclusive evidence about who is to blame for the chemical weapons attacks and again suggested the rebels were responsible. Rose said Assad also warned him previous U.S. military efforts in the region have proved disastrous.

And Assad argued the evidence Kerry has disclosed amounts to a “big lie” that resembles the case for war in Iraq that Secretary of State Colin Powell made to the United Nations over a decade ago.

Appearing Monday at a news conference in London with British Foreign Secretary William Hague, Kerry said of Assad: “What does he offer? Words that are contradicted by fact.”

“We know that his regime gave orders to prepare for a chemical attack. We know they deployed forces,” the secretary said. He added that the United States knows “where the rockets came from and where they landed ... and it was no accident that they all came from regime -controlled territory and all landed” in opposition-held territory.

“So the evidence is powerful and the question for all of us is, what are we going to do about it. Turn our backs? Have a moment of silence?”

He said that if Assad wanted to defuse the crisis, “he could turn every single bit of his chemical weapons over to the international community” within a week. But he said that Assad “isn’t about to do it.”

Pressed further on Assad’s denials, Kerry said, “I just answered that. I just gave you real evidence. Evidence that as a former prosecutor in the United States I could take into a courtroom and get admitted.”

Meanwhile, Russian and Syrian foreign ministers said they will push for the return of United Nations inspectors to Syria to continue their probe into the use of chemical weapons. Russia’s Sergey Lavrov said after Monday’s talks with his Syrian counterpart Walid al-Moallem that Moscow will continue to promote a peaceful settlement and may try to convene a gathering of all Syrian opposition figures who are interested in peaceful settlement.

Lavrov said that a U.S. attack on Syria will deal a fatal blow to peace efforts.

Obama plans a series of interviews Monday and will meet with Senate Democrats Tuesday to seek support for U.S. military action against the government of Syria, according to two Senate Democratic aides. The meeting at the Capitol would come just hours before Obama addresses the nation in a prime-time speech on Syria from the White House.

Former Secretary of State Hillary Rodham Clinton, who is scheduled to speak Monday at a White House event on wildlife trafficking, planned to reiterate her support of Obama’s efforts to pass the Syria resolution, according to a Clinton aide who spoke on condition of anonymity because the person was not authorized to speak publicly.

With Congress set to have its first votes authorizing limited strikes into Syria as early as Wednesday, Obama and his allies were arguing that the United States needs to remind hostile nations such as Iran and North Korea of American military might while working to reassure the nation that the lessons of the last decade were fresh in their minds.

“It is not Iraq, Afghanistan or Libya,” White House chief of staff Denis McDonough said Sunday during one of his five network television interviews. “This is a very concerned, concentrated, limited effort that we can carry out and that can underscore and secure our interests.”

But McDonough conceded the administration lacks “irrefutable, beyond-a-reasonable-doubt evidence” that skeptical Americans, including lawmakers who will start voting on military action this week, are seeking.

“It’s an uphill slog,” said Rep. Mike Rogers, the Republican chairman of the House Intelligence Committee, who supports strikes on Assad. “I think it’s very clear he’s lost support in the last week,” Rogers added, speaking of the president.

A survey by The Associated Press shows that House members who are staking out positions are either opposed to or leaning against Obama’s plan for a military strike by more than a 6-1 margin.

“Lobbing a few Tomahawk missiles will not restore our credibility overseas,” said Rep. Mike McCaul, the Texas Republican who chairs the House Homeland Security Committee.

Added Rep. Loretta Sanchez, D-Calif.: “For the president to say that this is just a very quick thing and we’re out of there, that’s how long wars start.”

Despite public backing from leaders of both parties to strike, almost half of the 433 current members in the House and a third of the 100-member Senate remain undecided, the AP survey found. They will be the subject of intense lobbying from the administration — as well as outside groups that have formed coalitions that defy the traditional left-right divide.

Public opinion surveys show intense American skepticism about military intervention in Syria, even among those who believe Syria’s government used chemical weapons on its people.

The United States, citing intelligence reports, says the lethal nerve agent sarin was used in an Aug. 21 attack outside Damascus, and that 1,429 people died, including 426 children.

Top administration officials, including Kerry, Defense Secretary Chuck Hagel and U.S. ambassador to the United Nations Samantha Power, planned to brief lawmakers ahead of the Wednesday vote on a resolution that would authorize the “limited and specified use” of U.S. armed forces against Syria for no more than 90 days.

The measure bars American ground troops from combat. A final vote is expected at week’s end and the House is expected to take up the issue the following week.